Reef Carbon, 2 quarts, Kent Marine. Removes organic pollutants, stains, and entrained toxic gases in marine and freshwater aquariums or ponds. Contains the finest pelletized activated bituminous coal based carbon. Pore size is in the 20 to 2,000 Angstrom range, ideally suited for removal of large organic molecules. Super activated with very high iodine and molasses numbers. Less than .2% ash making it suitable for sensitive species such as discus. Will not leach phosphates or promote undesirable algae growth. This item is a special order item only.